In flexbeam helicopter rotors, in which the flexible spar member is connected to the rotor hub through connecting pins passing through each, it has been the practice to wrap the high tensile strength fibers of the spar member around the connecting pins to obtain the required strength at that spar-to-hub joint, as shown in U.S. Pat. No. 3,476,484 to Brunsch dated Nov. 4, 1969. This prior art construction, however, has the disadvantage of creating an effective flapping hinge offset in the spar which is a substantial distance from the rotor axis of rotation. This, creates high interlaminar shear stresses within the spar due to a maximized load reaction between the spar and the connecting pins. In the prior art pin-wrap connections, the spar was made higher and thinner at the station where it wrapped around the connecting pin to maintain the high strength fibers in tension. It is further necessary to increase the height of the spar at the station where it wraps around the pin in the pin-wrap construction so as to reduce the thickness of the spar at that station since the stress K.sub.T created in the spar at the wrap-around station is about equal to the outer radius R.sub.o of the spar-wrap section divided by the inner radius R.sub.1 of the spar-wrap section, i.e., K.sub.T .congruent.Ro/Ri. Unfortunately, this increased spar root height added to the hinge offset problem. Further, the pin-wrap connection is difficult and expensive to fabricate.
It is also known in the prior art to use resilient pads between the spar and the supporting hub in crossbeam rotors in which there is no pin connection between the spar and the hub. Such pads were used solely for the purpose of preventing chaffing therebetween, and not for the purpose of decoupling blade flapping induced load paths in the spar-to-hub connection, since these dual load paths do not occur in cross-beam rotors. Further, cross-beam helicopter rotors require an even number of blades, and create difficulty in providing required precone and prepitch for optimum operation of the flexbeam, as well as difficulty in replacing a flexbeam.